diff options
Diffstat (limited to 'intl/uconv/ucvtw/nsUnicodeToBIG5.cpp')
| -rw-r--r-- | intl/uconv/ucvtw/nsUnicodeToBIG5.cpp | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/intl/uconv/ucvtw/nsUnicodeToBIG5.cpp b/intl/uconv/ucvtw/nsUnicodeToBIG5.cpp new file mode 100644 index 000000000..c3c9658df --- /dev/null +++ b/intl/uconv/ucvtw/nsUnicodeToBIG5.cpp @@ -0,0 +1,252 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "nsUnicodeToBIG5.h" + +NS_IMPL_ADDREF(nsUnicodeToBIG5) +NS_IMPL_RELEASE(nsUnicodeToBIG5) +NS_IMPL_QUERY_INTERFACE(nsUnicodeToBIG5, + nsIUnicodeEncoder) + +nsUnicodeToBIG5::nsUnicodeToBIG5() + : mUtf16Lead(0) + , mPendingTrail(0) + , mSignal(true) // as in nsEncoderSupport +{ +} + +NS_IMETHODIMP +nsUnicodeToBIG5::Convert(const char16_t* aSrc, + int32_t* aSrcLength, + char* aDest, + int32_t * aDestLength) +{ + const char16_t* in = aSrc; + const char16_t* inEnd = in + *aSrcLength; + uint8_t* out = reinterpret_cast<uint8_t*>(aDest); + uint8_t* outEnd = out + *aDestLength; + + MOZ_ASSERT(!(mPendingTrail && mUtf16Lead), + "Can't have both pending output and pending input."); + + if (mPendingTrail) { + if (out == outEnd) { + *aSrcLength = 0; + *aDestLength = 0; + return NS_OK_UENC_MOREOUTPUT; + } + *out++ = mPendingTrail; + mPendingTrail = 0; + } + for (;;) { + if (in == inEnd) { + *aSrcLength = in - aSrc; + *aDestLength = out - reinterpret_cast<uint8_t*>(aDest); + return mUtf16Lead ? NS_OK_UENC_MOREINPUT : NS_OK; + } + if (out == outEnd) { + *aSrcLength = in - aSrc; + *aDestLength = out - reinterpret_cast<uint8_t*>(aDest); + return NS_OK_UENC_MOREOUTPUT; + } + bool isAstral; // true means Plane 2, false means BMP + char16_t lowBits; // The low 16 bits of the code point + char16_t codeUnit = *in++; + size_t highBits = (codeUnit & 0xFC00); + if (highBits == 0xD800) { + // high surrogate + if (mUtf16Lead) { + // High surrogate follows another high surrogate. The + // *previous* code unit is in error. + if (mSignal) { + mUtf16Lead = 0; + // NOTE: Encode API differs from decode API! + --in; + *aSrcLength = in - aSrc; + *aDestLength = out - reinterpret_cast<uint8_t*>(aDest); + return NS_ERROR_UENC_NOMAPPING; + } + *out++ = '?'; + } + mUtf16Lead = codeUnit; + continue; + } + if (highBits == 0xDC00) { + // low surrogate + if (!mUtf16Lead) { + // Got low surrogate without a previous high surrogate + if (mSignal) { + // NOTE: Encode API differs from decode API! + *aSrcLength = in - aSrc; + *aDestLength = out - reinterpret_cast<uint8_t*>(aDest); + return NS_ERROR_UENC_NOMAPPING; + } + *out++ = '?'; + continue; + } + size_t codePoint = (mUtf16Lead << 10) + codeUnit - + (((0xD800 << 10) - 0x10000) + 0xDC00); + mUtf16Lead = 0; + // Plane 2 is the only astral plane that has potentially + // Big5-encodable characters. + if ((0xFF0000 & codePoint) != 0x20000) { + if (mSignal) { + // NOTE: Encode API differs from decode API! + // nsSaveAsCharset wants us to back up on step in the case of a + // surrogate pair. + --in; + *aSrcLength = in - aSrc; + *aDestLength = out - reinterpret_cast<uint8_t*>(aDest); + return NS_ERROR_UENC_NOMAPPING; + } + *out++ = '?'; + continue; + } + isAstral = true; + lowBits = (char16_t)(codePoint & 0xFFFF); + } else { + // not a surrogate + if (mUtf16Lead) { + // Non-surrogate follows a high surrogate. The *previous* + // code unit is in error. + mUtf16Lead = 0; + if (mSignal) { + // NOTE: Encode API differs from decode API! + --in; + *aSrcLength = in - aSrc; + *aDestLength = out - reinterpret_cast<uint8_t*>(aDest); + return NS_ERROR_UENC_NOMAPPING; + } + *out++ = '?'; + // Let's unconsume this code unit and reloop in order to + // re-check if the output buffer still has space. + --in; + continue; + } + isAstral = false; + lowBits = codeUnit; + } + // isAstral now tells us if we have a Plane 2 or a BMP character. + // lowBits tells us the low 16 bits. + // After all the above setup to deal with UTF-16, we are now + // finally ready to follow the spec. + if (!isAstral && lowBits <= 0x7F) { + *out++ = (uint8_t)lowBits; + continue; + } + size_t pointer = nsBIG5Data::FindPointer(lowBits, isAstral); + if (!pointer) { + if (mSignal) { + // NOTE: Encode API differs from decode API! + if (isAstral) { + // nsSaveAsCharset wants us to back up on step in the case of a + // surrogate pair. + --in; + } + *aSrcLength = in - aSrc; + *aDestLength = out - reinterpret_cast<uint8_t*>(aDest); + return NS_ERROR_UENC_NOMAPPING; + } + *out++ = '?'; + continue; + } + uint8_t lead = (uint8_t)(pointer / 157 + 0x81); + uint8_t trail = (uint8_t)(pointer % 157); + if (trail < 0x3F) { + trail += 0x40; + } else { + trail += 0x62; + } + *out++ = lead; + if (out == outEnd) { + mPendingTrail = trail; + *aSrcLength = in - aSrc; + *aDestLength = out - reinterpret_cast<uint8_t*>(aDest); + return NS_OK_UENC_MOREOUTPUT; + } + *out++ = trail; + continue; + } +} + +NS_IMETHODIMP +nsUnicodeToBIG5::Finish(char* aDest, + int32_t* aDestLength) +{ + MOZ_ASSERT(!(mPendingTrail && mUtf16Lead), + "Can't have both pending output and pending input."); + uint8_t* out = reinterpret_cast<uint8_t*>(aDest); + if (mPendingTrail) { + if (*aDestLength < 1) { + *aDestLength = 0; + return NS_OK_UENC_MOREOUTPUT; + } + *out = mPendingTrail; + mPendingTrail = 0; + *aDestLength = 1; + return NS_OK; + } + if (mUtf16Lead) { + if (*aDestLength < 1) { + *aDestLength = 0; + return NS_OK_UENC_MOREOUTPUT; + } + mUtf16Lead = 0; + if (mSignal) { + *aDestLength = 0; + return NS_ERROR_UENC_NOMAPPING; + } + *out = '?'; + *aDestLength = 1; + return NS_OK; + } + *aDestLength = 0; + return NS_OK; +} + +NS_IMETHODIMP +nsUnicodeToBIG5::GetMaxLength(const char16_t* aSrc, + int32_t aSrcLength, + int32_t* aDestLength) +{ + *aDestLength = (aSrcLength * 2) + + (mPendingTrail ? 1 : 0) + + // If the lead ends up being paired, the bytes produced + // are already included above. + // If not, it produces a single '?'. + (mUtf16Lead ? 1 : 0); + return NS_OK; +} + +NS_IMETHODIMP +nsUnicodeToBIG5::Reset() +{ + mUtf16Lead = 0; + mPendingTrail = 0; + return NS_OK; +} + +NS_IMETHODIMP +nsUnicodeToBIG5::SetOutputErrorBehavior(int32_t aBehavior, + nsIUnicharEncoder* aEncoder, + char16_t aChar) +{ + switch (aBehavior) { + case kOnError_Signal: + mSignal = true; + break; + case kOnError_Replace: + mSignal = false; + MOZ_ASSERT(aChar == '?', "Unsupported replacement."); + break; + case kOnError_CallBack: + MOZ_ASSERT_UNREACHABLE("kOnError_CallBack is supposed to be unused."); + break; + default: + MOZ_ASSERT_UNREACHABLE("Non-existent enum item."); + break; + } + return NS_OK; +} |